Polishing pad

ABSTRACT

An improved polishing pad for polishing semi-conductors and other planar substrates in the presence of a slurry which optionally may contain abrasive particles is disclosed. The polishing pad comprises a non-woven fibrous component, a portion which may optionally comprise bicomponent fibers, optionally embedded within a polymer matrix component.

FIELD OF THE INVENTION

The present invention relates to polishing pads and more particularly toa novel composition and method for forming polishing pads. The polishingpads of the present invention are especially useful inchemical-mechanical planarization of substrates during the manufactureof semi-conductor and related devices. The invention relates to padscomprising a needle-punched non-woven textile, a portion or the entiretyof which may comprise bicomponent fibers, optionally embedded in apolymeric binder. The pads are suitable for chemical-mechanicalpolishing, either with or without a need for abrasives to be included inthe polishing slurry. The pads formed from the needle-punched non-woventextile and optional polymeric binder may be processed in a manner tosupply pads having unique hardness characteristics that have been foundmore suitable for the polishing operation. In addition, the pads of thepresent invention may be produced using an uncomplicated continuousprocess.

BACKGROUND OF THE INVENTION

For many years, optical lenses and semiconductor wafers have beenpolished by chemical-mechanical means. More recently, this technique hasbeen applied as a means of planarizing intermetal dielectric layers ofsilicon dioxide and for removing portions of conductive layers withinintegrated circuit devices as they are fabricated on various substrates.For example, a conformal layer of silicon dioxide may cover a metalinterconnect such that the upper surface of the layer is characterizedby a series of non-planar steps corresponding in height and width to theunderlying metal interconnects.

The rapid advances in semiconductor technology has seen the advent ofvery large scale integration (VLSI) and ultra large scale integration(ULSI) circuits resulting in the packing of very many more devices insmaller areas in a semiconductor substrate. The greater device densitiesrequire greater degrees of planarity to permit the higher resolutionlithographic processes required to form the greater number of deviceshaving smaller features incorporated in current designs. Moreover,copper, because of its low resistance, is increasingly being used asinterconnects. Conventionally, etching techniques are used to planarizeconductive (metal) and insulator surfaces. However, certain metals,desirable for their advantageous properties when used as interconnects(Au, Ag, Cu) are not readily amenable to etching, thus the need forchemical-mechanical polishing (CMP).

Typically, the various metal interconnects are formed throughlithographic or damascene processes. For example, in a lithographicprocess, a first blanket metal layer is deposited on a first insulatinglayer, following which electrical lines are formed by subtractiveetching through a first mask. A second insulating layer is placed overthe first metallized layer, and holes are patterned into the secondinsulating layer using a second mask. Metal columns or plugs are formedby filling the holes with metal. A second blanket metal layer is formedover the second insulating layer, the plugs electrically connecting thefirst and second metal layers. The second metal layer is masked andetched to form a second set of electrical lines. This process isrepeated as required to generate the desired device. The damascenetechnique is described in U.S. Pat. No. 4,789,648, to Chow, et al.

Presently, VLSI uses aluminum for the wiring and tungsten for the plugsbecause of their susceptibility to etching. However, the resistivity ofcopper is superior to either aluminum or tungsten, making its usedesirable, however copper does not have desirable properties withrespect to etching.

Variations in the heights of the upper surface of the intermetaldielectric layer have several undesirable characteristics. The opticalresolution of subsequent photolithographic processing steps may bedegraded by non-planar dielectric surfaces. Loss of optical resolutionlowers the resolution at which lines may be printed. Moreover, where thestep height is large, the coverage of a second metal layer over thedielectric layer may be incomplete, leading to open circuits.

In view of these problems, methods have been evolved to planarize theupper surfaces of the metal and dielectric layers. One such technique ischemical-mechanical polishing (CMP) using an abrasive polishing agentworked by a rotating pad. A chemical-mechanical polishing method isdescribed in U.S. Pat. No. 4,944,836, to Beyer, et al. Conventionalpolishing pads are made of a relatively soft and flexible material, suchas non-woven fibers inter-connected together by a relatively smallamount of a polyurethane adhesive binder, or may comprise laminatedlayers with variations of physical properties throughout the thicknessof the pad. Multilayer pads generally have a flexible top polishinglayer backed by a layer of stiffer material.

The CMP art combines the chemical conversion of the surface layer to beremoved, with the mechanical removal of the conversion product. Ideally,the conversion product is soft, facilitating high polishing rates. CMPpads must resolve two constraints relevant to the present invention. Thesurface in contact with the substrate to be polished must be somewhatresilient. Of particular relevance to the present invention is theproblem of local over-polishing, also known as “dishing.” This is one ofthe key problems encountered during CMP of metal substrates. It isgenerally known that prevention of dishing requires a stiffer pad.However, associated with stiffer pads is the tendency towards anincreased number and density of surface scratches and defects. Suchdefects correlate with low yields of product.

Some of the most commonly used polishing pads for manufacturingsemi-conductor chips are a very soft foam pad, or a soft non-woven fiberpad. An advantage of a soft polishing pad is low defect density on thepolished wafer and good within-wafer uniformity. However, soft CMP padssuffer from very short pad life requiring replacement after polishingabout 50 wafers, and excessive dishing of the polished wafer because ofthe pad softness. Also, for a metal damascene CMP process, a soft padusually causes much more dishing compared with a hard pad.

It is generally known that prevention of dishing requires a stiffer pad.Thus, a hard polishing pad usually has better planarization capabilitythan a soft pad. However, the defects count is much higher than with thesoft pad and the within-wafer uniformity is usually much worse. Inaddition, hard pads may be conditionable, which means that the padsurface condition can be regenerated using a diamond disk or an abrasiveroller to recondition the pad surface by removing worn areas andembedded debris. This reconditioning capability means that a hard padmay last much longer than a soft pad. Such reconditioning in situ alsomeans that polishing tool down-time for pad replacement is greatlyreduced.

Currently, these problems are handled using multi-step techniqueswherein initial polishing is effected at a high rate using one set ofpads and abrasive compounds, followed by a second polishing step using asecond set of pads and abrasive compounds differently optimized incomparison to the first set. This is a time-consuming process and,moreover, it also suffers from high defect densities due to the use oftwo different pads. For Cu planarization, CMP pads are critical, and areas important as the abrasive slurry. The prior art has suggested that asingle-layered pad was either too stiff or too soft to obtain goodplanarization. Stacked non-woven and other types of pads have previouslybeen tried in an attempt to obtain better CMP performance. However, thin(5 to 20 mil thick) fibrous pads have not been sufficiently durable anddo not survive the CMP process.

Accordingly, the need exists for improved fibrous polishing pads. A highquality pad should meet the following requirements: produce extremelylow defects counts on polished surfaces, cause extremely small dishingand extremely low erosion of polished surfaces, and have a long pad lifeextendible by reconditioning. None of the existing prior art CMP padscan meet all of these requirements, which are needed for the futuregeneration of CMP processes. A new type of CMP pad is therefore neededto meet these requirements, particularly one manufactured by anuncomplicated continuous process.

SUMMARY OF THE INVENTION

In one embodiment, the present invention is directed at a pad forpolishing a substrate comprising a first component comprising anon-woven fibrous component, at least a portion of which or the entiretyof which optionally comprises bicomponent fibers, and optionally asecond component comprising a polymer matrix component, said fibrouscomponent embedded in said polymer matrix component.

In method form, the present invention comprises a process formanufacturing a polishing pad, comprising the steps of providing anon-woven fibrous component, at least a portion of which or the entiretyof which optionally comprises bicomponent fibers, optionally providing apolymer matrix to coat said non-woven fibrous component, combining saidnon-woven fibrous component with said polymer matrix, and subjectingsaid polymer matrix and non-woven fibrous component to a temperaturerange “T” and pressure to solidify and form a composite sheet for use assaid polishing pad. In such process the bicomponent fiber may includeone component with a melting point of Tm₁, one component with a meltingpoint Tm₂, wherein Tm₁<Tm₂, and wherein Tm₁ is within temperature range“T”. Alternatively, one may employ a binder fiber which has a meltingpoint with the temperature range “T”.

The present invention also relates to a polishing pad for polishing asubstrate in the presence of a slurry which may or may not containabrasive particles. The polishing pad herein is also suitable formanufacture via a continuous manufacturing process.

The pads in certain embodiments may also be characterized as arelatively thin, stiff and hard construction. The polishing propertiesof the top layer of the pad of the present invention may be uniquelyvaried by the choice and characteristics of non-woven fibers used, bythe choice of the optional polymeric matrix (binder) used and by theincrease in density of the non-woven textile compared to the finishedpad due to the level of saturation and compression used in the padmanufacturing process.

The present invention also relates to a method of producing theabove-disclosed polishing pad. In particular, the method comprisescombining a needle-punched non-woven textile, at least a portion ofwhich or the entirety of which may comprise bicomponent fibers, with apolymeric binder to a desired level and forming a thin sheet under heatand pressure, followed by surface finishing. The application of heat andpressure serves to activate a portion of the bicomponent fibers resultsin a sheet with improved physical properties. The application ofpressure further serves to control the thickness and density of thesheet. The sheet is cut to shape and may optionally be backed with asubstrate to form a polishing pad. The polishing pad of the presentinvention may be applied to a diversity of applications includingsemiconductor wafer polishing known as chemical mechanical polishing(CMP) and other polishing applications for metal, ceramic, glass,wafers, hard disks etc., that employ a liquid medium as a polishingslurry.

DESCRIPTION OF THE DRAWINGS

The invention may be further understood by reference to the detaileddescription below taken in conjunction with the accompanying drawings,in which:

FIG. 1 is a schematic of one preferred manufacturing process accordingto the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Still other objects and advantages of the present invention will becomereadily apparent to those skilled in the art from the following detaileddescription, wherein preferred embodiments of the invention are shownand described, and as illustration of the best mode contemplated ofcarrying out the invention. As will be realized by the skilled person,the invention is capable of other and different embodiments, and itsdetails are capable of modifications in various respects, withoutdeparting from the invention.

A polishing pad comprises a first fibrous non-woven polymer componentoptionally embedded in a second polymer matrix (binder) component.Typical non-woven textiles suitable for use in this invention as thefibrous component of the polishing pad are preferably polyester,although polypropylene, polyamide, acrylic, polyethylene, cellulosicmaterials, such as rayon, and combinations of these fibers may be used.In particular, bicomponent fibers, wherein the core and sheath materialsmay be different from one another, or in a side-by side configuration,may be preferably used as at least a portion of the fibrous component oras the entire fibrous component. The listed fibers are meant to beillustrative of the types that may be used, but the invention is notthereby limited to the enumerated types. The fiber component may bepreferably present at levels between 10–90% (wt) with respect to thepolymer matrix (binder) component.

The fibers and matrix polymers together typically form a pad, or thefibers alone may form the pad, which in either case has a hardness ofabout 10 Shore D to about 70 Shore D, and preferably about 30 Shore D toabout 70 Shore D, as measured by Durometer Hardness test method ASTMD2240. In addition, all hardness ranges within said ranges may beemployed for the preparation of the polishing pads disclosed herein.Accordingly, hardness values of 10D, 11D, 12D and so on, up to apreferred level of 70D are contemplated herein.

The optional bicomponent fibers employed herein, preferably of asheath-core construction, or a side-by-side configuration, and providean advantageous feature as the melting point of one of the componentsmay be configured to match the temperature attained in the pressing andcuring process. Alternatively, one may employ a binder fiber, which alsomay have a melting point that is within the range of temperaturesachieved in the pressing process. Without being bound by theory, it isbelieved that this may allow for an improved level of binding betweenthe fibers and the polymer matrix component. However, in the broadcontext of the present invention, and as discussed more fully herein, asheath-core construction is not the only form of bicomponent fibers, asthe invention herein contemplates bicomponent fibers of otherconstructions, such as a physical blend of two fibers.

Useful polymeric materials for the polymer matrix component include mostcommon thermoplastic and thermosetting polymers, in any physical formsuch as a polymer dispersion and/or non-dispersions such as solutionsand/or pure resins, and include, but are not limited to polymers such aspolyurethanes, polyacrylates, polystyrenes, polyamides, polycarbonates,and epoxies. Other polymers that have a rigidity sufficient to supportthe fibrous component may also be used. In this regard, it can beappreciated that such polymer matrix components themselves may have amelting point (in the case of crystalline polymers), softeningtemperature (in the case of amorphous polymers), and/or curingtemperature (in the case of thermoset polymers) which allows suchpolymer matrix component to be processed with the above referencedfibrous component to form the polishing pads of the present invention.

The fibrous component is preferably in the form of a non-woven web ormat, which has preferably been needle-punched to a basis weight of about100 to about 2500 grams per square meter, and at any value or any rangetherebetween. For example, the range may be between about 300–1500 gramsper square meter. The optional bicomponent fibers or binder fibers maybe combined with the preferably non-woven polymer at any desiredproportion, or the bicomponent fibers may completely replace thenon-woven polymer component.

The chemical-physical properties, hence the polishing performance, ofthe fiber and polymer composite are governed by the types and sizes ofthe fibers, the types and hardness of the polymers, the fiber to polymerratio, the friability of the polymers, and the local and globaldistribution of the polymer matrix within the fiber mat. For examplepurposes, employing a larger denier fiber (thus with fewer fibers for agiven density of the fiber mat) and the use of a high fiber:polymerratio will typically result in a pad structure having a lower overalldensity and surface hardness, and a higher compressibility as comparedto the use of smaller denier fiber. In addition, and by way of example,if fiber denier is held constant, the polymer matrix material can bealtered to influence density and hardness characteristics of the finalpad product.

As alluded to above, the optional use of bicomponent fibers as a portionof the fiber mat of the present invention provides some uniqueproperties to the polishing surface of the polishing pad. Bicomponentfibers are produced by extruding two polymers from the same spinnerettewith both polymers contained within the same filament. While there are anumber of constructions of bicomponent fibers (side-by-side,matrix-fibril, pie-wedge, islands/sea, etc.), a sheath/core constructionis preferred in the present invention wherein the surrounding sheathportion comprises a polymer having a lower melting temperature than thepolymer of the core portion.

As noted, the pads of the present invention may comprise about 10 toabout 100 percent by weight of the fibrous component, the 100 percentlevel referring to that optional embodiment where the pad is composedentirely of the fibrous component, and wherein the numbers less than 100percent correspond to that optional embodiment which includes apolymeric component. Accordingly, in the event that the fibrouscomponent does not comprise 100 percent of the pad, and a polymericcomponent is employed, such polymeric component may be present at anycorresponding level to make-up for the reduction from 100% for thefibrous component. However, in preferred embodiment, the polymericcomponent may be present at levels of about 10–90 percent, or at anyother individual percentage or range, e.g., at a level of about 40percent to 60 percent by weight.

In addition, the pads of any of the embodiments of the present inventionmay have a preferred thickness range of about 0.5 mm to 5.0 mm, and atany value or range therebetween. Accordingly, e.g, the thickness rangemay be between about 0.5 mm to 3.0 mm.

To preferably develop a desired hardness in the pad, the fibrouscomponent preferably comprises a relatively loose network of fibers andthis network is substantially completely filled with the polymericmatrix binder material to form a composite in which the fibrouscomponent becomes embedded after the polymer is solidified. Thesolidified polymer preferably forms a relatively hard but friablematrix. After the sheet has been pressed to the final thickness, the topsurface of the sheet may be conditioned by buffing with a diamond diskor opposing inline abrasive rollers to remove the skin-like polymersurface and expose about a 1 to 2 mil thickness (0.025 to 0.052 mm) ofthe fiber mat, which thereby creates about a 1 to 2 mil thick fibersurface layer containing fibers that are partially free. The creation ofthis surface layer results from the friable nature of the cured polymermatrix. In other words, the strength of the fiber is stronger than thebinder or polymer matrix material such that, during buffing, the binderis removed at the surface while the surface fibers remain attached tothe fiber and polymer composite. Thus, after buffing, a small thicknessof depth of surface polymer is removed to leave a thin surface layer offree fibers, segments of at least a portion of which remain embedded inthe adjacent composite body of polymer and fibers. During CMP processes,this fibrous polishing surface helps to reduce the defects count causedby using a conventional hard pad. In addition, the solid matrix formedby the polymer densely filling the fiber mat or fibrous component hereinpreferably increases the hardness of the pad.

Accordingly, the thin fibrous surface layer of the preferred pad of thepresent invention significantly reduces the defects count of the waferspolished therewith, and the hard stiff body results in much less dishingof the polished wafer surface. As a result, metal dishing can beminimized. In addition, erosion of the wafer surface is reduced.

In addition, the top layer surface of the pads herein may bereconditioned after polishing one or more wafers to maintain a highperformance level. This makes the pad service life much longer thanconventional soft fiber-based pads. The conditioning process canactually recreate the thin (about 1 to 2 mils) fibrous surface layerwhich continues to help reduce the defects count, while the underlyinghard fiber and polymer body sufficiently fixes and supports the fiberlayer to reduce the dishing phenomenon.

Optionally, to form a polishing pad, an adhesive-backed structure may beattached to the backing surface of the composite as an alternate meansto affix the pad to a tool. The backing structure may provide a mediumfor attaching the polishing pad to a tool and add compressibility tocomplement the rigidity of the composite material layer. The rigidity ofthe composite material layer provides planarity on a small scale, thatis, over a small region of the substrate to be polished. Thecompressibility of the backing structure provides uniformity of pressureover the entire substrate surface, for example over the 8 inch or 12inch diameter of a semi-conductor wafer. This ensures uniformity ofpolishing if, for example, the substrate is concavely or convexly curvedor otherwise irregular.

Alternatively, the present invention herein contemplates the use of,e.g., a Mylar™ film, containing pressure sensitive adhesive (PSA) onboth sides of the polymeric film utilized therein to facilitateattachment to a tool. In this situation, it is contemplated that suchMylar™ film will provide more of an incompressible layer, but stillefficiently serve as a means of attachment of the pad to the tool foreffective polishing.

In addition, in yet another further optional embodiment, the polishingpads of the present invention may include a fibrous or particle (e.g.powder) component that is soluble or swellable in the polishing slurry,such that fibers or particles of the present invention may dissolve uponcontact with the slurry, including slurries that are either water basedor non-water based. In semiconductor wafer polishing the slurry istypically an aqueous medium, and the solvent is typically water.

Such additional fibrous or particle component may therefore be formed ofvarious suitable polymer materials, preferably including poly(vinylalcohol), derivatives of poly(vinyl alcohol), copolymers of poly(vinylalcohol), polyacrylic acid, derivatives of polyacrylic acid, copolymersof polyacrylic acid, polysaccharides, derivatives of polysaccharides,copolymers of polysaccharides, gums, derivatives of gums, copolymers ofgums, maleic acid, derivatives of maleic acid, or copolymers of maleicacid. Such fibrous or particle component is also preferably prepared byany suitable process, such as be nonwoven techniques, for examplechemical, mechanical or thermal bonding of fibers or the laying down ofa loose mat of fibers or filaments as well as by weaving or knittingtechniques. In addition, the orientation of these optional fibersrelative to the polishing surface may be controlled, e.g., such fibersmay be orientated predominantly parallel to the surface, or preferablyin an orthogonal configuration. The fibers or particles, being soluble,may also be selected such that after dissolution, a pore is formed,wherein such pore size is complimentary to the particle size of anabrasive particle that may be in the slurry. Such abrasive particlestypically range in size from 100–200 nm. Accordingly, a fiber diameterrange of 20–200 μm is preferably employed, which has been found toprovide the optimum size for interacting with the particles of theslurry to optimize wafer polishing. Furthermore, the optional soluble orswellable fibers of particles noted above may be present in thepolishing pad herein at levels between 10% (wt) to 90% (wt).

The process for forming one embodiment of the polishing pad of thepresent invention, i.e. that embodiment that combines the fibercomponent with the polymer matrix component, will now be described. Withattention directed to FIG. 1, the non-woven fibers, optionally includingthe bicomponent fibers, can be needle-punched to form a mat. This isfollowed by impregnation with the polymer matrix component using aprocess such as, but not limited to, spraying, dipping, knife-over-roll,or transfer coating to substantially saturate the mat with binder. Themat is then heated with the polymer matrix component to an effectivelydry condition. Then, the dried material is cut into a sheet. Then, afterheating to dry as noted above, the process is followed by application ofheat and pressure to the sheet to set the density and thickness. Suchtemperatures may preferably fall in the range of about 200–550° F., andthe pressures may be preferably be up to 2000 psi, or within the rangeof about 500–2000 psi. The sheet so formed is then buffed to removepolymer matrix skin material to form the polishing surface, and thesheet can then be conveniently cut to a desired shape. Optionally, afterbuffing, an adhesive layer may be applied to the sheet. In addition,after cutting into a desired shape, the polishing pad may be convertedin any conventional manner, such as the incorporation of other physicalfeatures into the pad (e.g. grooving) to further improve polishingperformance.

In an alternative process, one can avoid the use of the polymeric matrixcomponent, and make use of the non-woven component. In this situation,the non-woven is cut into sheet, and heated and pressed to set thedensity and thickness, similarly at preferred temperatures of about200–550° F. and pressures up to about 2000 psi, and cut into a desiredshape, and also optionally converted as noted above.

Table I below summarizes the working examples of the pads that weremanufactured according to the general methods of the present invention.

TABLE I Pad Composition Pad Composition Pad Composition 75% 15% Bico 15%Bico 75% Bico Bicomponent/Two Binder: UD220 Binder 1049C Binder UD220Pads Pressed Physical [40–60% wt.] [40–60% wt.] [40–60% wt.] Together*Property (40%–60%) (40%) (60%) (40%) (60%) 60% Binder UD220 Thickness(mm)  .5–1.5  .5–1.5  .5–1.5 1.0–2.0 Weight (g/m2) 400–700 400–750350–750  700–1400 Density (g/cc)  .4–1.0  .4–1.0  .5–1.0  .6–1.0Hardness 30–70 30–70 30–70 30–70 (ShoreD) Compressibility 1.0–4.01.0–4.0 1.0–4.0  .5–2.0 (%) All data in Table I applies to buffed andpressed pads Bondthane UD220 (Bond Adhesives & Coatings Corp)(aliphaticpolyester urethane dispersion) Sancure 1049C (Noveon SpecialtyChemicals)(aliphatic waterborne urethane polymer) *Two pads pressedtogether were 60% binder and 75% bicomponent, pressed together at about20,000 lbs. at 300° F.

In addition, it can be seen from the above that in yet another preferredembodiment of the present invention, two pads may be pressed/bondedtogether. In such case, thickness naturally increases, andcompressibility decreases. Accordingly, the present inventioncontemplates one or a plurality of pad layers for a polishing padapplication.

Furthermore, as noted herein, the present invention contemplates the useof a needle punched non-woven fiber web, without a polymer matrixcomponent, at a basis weight of 1000 g/m². Such product is contemplatedas having a thickness of 1.5–2.5 mm, a density of 0.5–1.0 g/cc, ahardness of 30D–70D, and a compressibility of 0.5–2.0%.

In addition, it should be noted that “Compressibility” in Table I isestablished by the following procedure: Test samples are specified. Testequipment is an Ames gages (Model BG2600-1-04). First one determines theinitial thickness using one specified Ames gage which has a 287 gramloading, ½″ diameter anvil and ⅜″ diameter foot (plunger). One thenrandomly selects one spot on the sample which is marked with an “X”.This is followed by gently placing the “X” spot between the foot andanvil of the gage and one records the thickness reading as it appears onthe digital readout after it becomes stable. One then determines thefinal thickness using another specified Ames gage with has a 795 gramloading, ½″ diameter anvil and 3/16″ diameter foot (plunger) as follows:One gently places an “X” spot between the foot and anvil of the gage andrecords the thickness reading as it appears on the digital readout whenit becomes stable. All thickness data are recorded. One calculates the %compressibility by using the following formula: %Compressibility=(Initial Reading−Final Reading/Initial Reading)×100%.

It should be clear from the above description and comparison ofproperties that the present invention provides a process for producing apolishing pad in an uncomplicated continuous manner. The pads formed bythis process may provide a wide latitude of properties due to thecombinations of compositions that are possible. Further, a novel meansfor providing improved fiber to binder adhesion is provided through theuse of bicomponent fibers and matching the molding conditions of the toplayer to the melting point of the sheath component of the bicomponentfibers used.

The polishing pad of the present invention is particularly suitable forthe chemical mechanical polishing of semi-conductor wafers. Thepolishing pad may, however, be used for polishing other substrates, suchas metal, ceramic, glass, wafers, or hard disks, in polishingapplications that use a liquid medium to carry and disperse abrasiveparticles between the polishing pad and the substrate being polished.Having described preferred embodiments of the invention it will nowbecome apparent to those of ordinary skill in the art that otherembodiments incorporating the concepts of the present invention may beused. Accordingly, it is submitted that the invention should not belimited by the described embodiments but rather should only be limitedby the spirit and scope of the appended claims.

1. A process for manufacturing a polishing pad, comprising the steps of:(a) providing a non-woven fibrous component at a basis weight of100–2500 g/m², wherein said non-woven fibrous component comprisesbicomponent fibers with two polymers contained within the same filament;(b) providing a polymer matrix to coat said non-woven fibrous component;(c) combining said non-woven fibrous component with said polymer matrix;and (d) subjecting said polymer matrix and non-woven fibrous componentto a temperature range and pressure to set density and thickness andform a composite sheet, and wherein said pad has a Shore D hardness ofbetween about 10D to 70D.
 2. The process of claim 1 wherein saidbicomponent fibers include one component with a melting point of Tm₁,one component with a melting point Tm₂, wherein Tm₁<Tm₂, and wherein Tm₁is within said temperature range.
 3. The process of claim 1 wherein saidfibrous component includes a binder fiber with a melting point that iswithin said temperature range.
 4. The process of claim 1 wherein saidtemperature range is about 200–550° F.
 5. The process of claim 1 whereinsaid pressure is up to about 2000 psi.
 6. The process of claim 1 whereinsaid pressure is between about 500–2000 psi.
 7. The process of claim 1wherein said composite sheet includes a top surface and said top surfaceis abraded.
 8. The process of claim 1 further including the step ofcutting said composite sheet into shape to form said polishing pad. 9.The process of claim 1 wherein said bicomponent fibers are of asheath/core configuration.
 10. The process of claim 1 wherein thebicomponent fibers are comprised of polyethylene, polyethyleneterephthalate, polyester, polyamide or polypropylene.
 11. The process ofclaim 1 wherein the polymeric matrix component comprises a polyurethane,a polyacrylate, a polystyrene, a polyimide, a polyamide, apolycarbonate, an epoxy or combinations thereof.
 12. The process ofclaim 1 further comprising providing a soluble or swellable polymerwhich solubilizes or swells in a polishing slurry.